1. Field of the Invention
The present invention relates to mass spectrometry systems. More particularly, it relates to mass spectrometry systems that are useful for the analysis of complex mixtures of molecules, including large and small organic molecules such as proteins or peptides, environmental pollutants, pharmaceuticals and their metabolites, and petrochemical compounds, to methods of analysis used therein, and to a computer program product having computer code embodied therein for causing a computer, or a computer and a mass spectrometer in combination, to affect such analysis.
2. Prior Art
A previous approach, as in U.S. Pat. No. 6,983,213, International Patent Application PCT/US2005/039186, filed on Oct. 28, 2005, and U.S. provisional patent application Ser. No. 60/941,656, filed on Jun. 2, 2007 provides a novel method for calibrating mass spectra for improved mass accuracy and line shape correction to improve the ability to perform elemental composition analysis or formula identification.
Very high mass accuracy can be obtained on so-called unit mass resolution systems in accordance with the techniques taught in U.S. Pat. No. 6,983,213.
Accurate line shape calibration provides an additional metric to assist in the unambiguous formula identification by matching the measured spectra to the calculated spectra of candidate formulas, as in International Patent Application PCT/US2005/039186, filed on Oct. 28, 2005.
For higher resolution mass spectrometers where the monoisotopic peak is baseline resolved from the rest of the isotopes, accurate line shape calibration can be performed even without the use of either internal or external calibration standards by simply using the monoisotopic peak of the unknown ion itself as the peak shape calibration standard, as in U.S. provisional patent application Ser. No. 60/941,656, filed on Jun. 2, 2007.
However, obtaining correct elemental compositions from conventional to high resolution mass spectrometry systems remains a challenge to practitioners of mass spectrometry due to the enormous number of possible formulas within a given accurate mass tolerance and the highly tedious process of deciding which elements to consider for the elemental composition.
There exists a significant gap between what the current mass spectral system can offer and what is being achieved at the present using existing technologies for mass spectral analysis.